PORTAGE_CHECKSUM_FILTER = [space delimited list of hash names]
This variable may be used to filter the hash functions that are used to verify integrity of files. Hash function names are
case-insensitive, and the * and -* wildcard tokens are supported.
Defaults to the value of *.
Examples:
# Use all available hash functions
PORTAGE_CHECKSUM_FILTER="*"
# Use any function except whirlpool
PORTAGE_CHECKSUM_FILTER="* -whirlpool"
# Only use sha256
PORTAGE_CHECKSUM_FILTER="-* sha256"

PORTAGE_CHECKSUM_FILTER = [space delimited list of hash names]
This variable may be used to filter the hash functions that are used to verify integrity of files. Hash function names are
case-insensitive, and the * and -* wildcard tokens are supported.
Defaults to the value of *.
Examples:
# Use all available hash functions
PORTAGE_CHECKSUM_FILTER="*"
# Use any function except whirlpool
PORTAGE_CHECKSUM_FILTER="* -whirlpool"
# Only use sha256
PORTAGE_CHECKSUM_FILTER="-* sha256"

You have disabled ALL checksum hash functions. You need to enable at least one._________________"Those who deny freedom to others deserve it not for themselves." - Abraham Lincoln
Free Culture | Defective by Design | EFF

no, changing dependency painful, so I still decided to update existence.

Which means, you changed the ebuild, which no longer matches the hashes (sha1, sha256, whirlpool).

easiest way, is to copy the file (and all depending files - usually the entire files folder is enough, if not an overkill) to a local overlay, change whatever is nescessary, then rebuild the checksum using ebuild /path/to/ebuild digest. alterntively - but i strongly advise against it - you can use the --digest in the emerge command._________________read the portage output!
If my answer is too concise, ask for an explanation.